The present invention relates to a light radiator, in particular, a light radiator unitarily comprising a movable light source corresponding to the direct solar rays transmitted directly and a fixed light source corresponding to the indirect solar rays.
The present applicant has previously proposed various ways to focus solar rays or artificial light rays by use of lenses or the like, to guide the same into an optical conductor cable, and thereby to transmit them onto an optional desired place through the optical conductor cable. The solar rays or the artificial light rays transmitted and emitted in such a way are employed for photo-synthesis and for use in illuminating or for other like purposes, for example, to promote the cultivation of plants.
However, in the case of utilizing the light energy for cultivating plants as mentioned above, the light rays transmitted through the optical conductor cable has directional characteristics. Supposing that the end portion of the optical conductor cable is cut off and the light rays are emitted therefrom, the radiation angle for the focused light rays is, in general, equal to approximately 46.degree.. That is quite a narrow field. In the case of utilizing the light energy as described above, it is impossible to perform a desirable amount of illumination by simply cutting off the end portion of the optical conductor cable and by causing the light rays to emit therefrom.
Therefore, the present applicant has already proposed various kinds of light radiators capable of effectively diffusing the light rays which have been transmitted through an optical conductor cable and radiating the same for illumination over a desired area.